In the context of reducing CO2 emissions and developing high-efficiency alternators, the synchronous rectification technology applied to alternators for motor vehicles has a certain interest.
Synchronous rectification uses a bridge rectifier with power transistors, generally of the MOSFET type. Control electronics are also provided for shaping suitable control signals for the power transistors.
Compared with conventional alternator technology with a diode bridge rectifier, the proportion of electronics in synchronous rectification machines is increasing significantly.
In terms of cost, the proportion of electronics in a synchronous rectification machine may be between 30% and 50% of the total cost of the machine. By way of comparison, the proportion of the cost of the electronics in diode bridge rectification machines is around 25%. A breakdown in the electronics requiring a replacement of the faulty part may therefore give rise to appreciable cost repercussions in after-sales service operations.
Reliability of the electronics is essential for the overall reliability of the machine and gives rise to novel constraints for the designers. These constraints are all the more severe since the current trend in motor manufacturers is to extend the guarantee period for the vehicles.
It is therefore desirable to propose solutions affording an improvement in the overall reliability of a synchronous rectification alternator and, more particularly, the reliability of the electronics in such a alternator.